Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[mark.adams]

Fitted new O2 sensor as "My Naff Code Reader" had reported it as failed, no errors now but failed emissions on idle on  both LPG and petrol...
Any ideas??

[Kevin Wood]

Can you post the readings from the emission test report? perhaps we can deduce something from it.

Kevin

[mark.adams]

natural idle CO max limit 0.5 actual value 5.088
fast idle max limit 0.3 actual value 0.460

[Kevin Wood]

natural idle CO max limit 0.5 actual value 5.088
fast idle max limit 0.3 actual value 0.460

  That must be running seriously rich. Does it run smoothly? Any fault codes reported by the ECU? Does the car drive OK?

Kevin

[Elite Pete]

What condition is the air filter in?

[mark.adams]

It's a little lumpy occasionally, the only fault reported was the O2 sensor and hasn't been reported since i replaced it over the weekend...
that was sensor 1 heater failed, so i replaced it and the error never came back
What causes it to run rich??

[mark.adams]

What condition is the air filter in?

Good point, i hadn't checked that, i'll replace it as it hasn't been changed recently

[mark.adams]

Could the cat be suspect, i recently replaced the exhaust from cat back...

[Kevin Wood]

I would say with a CO level that high, there needs to be a problem with the mixture the engine's burning. Pre-cat CO levels are typically less than 2% IME.

Kevin

[mark.adams]

soooo if its running too rich, that means there's too much fuel and not enough air, as it does it on LPG as well as petrol that rules out the injectors (the LPG is a mixer system) i am looking at not enough air getting in.... does that sound right??

[mathewst]

Did you ever clean the breathers and the egr valve?

[Marks DTM Calib]

What does "My Naff Code Reader" say the coolant temperature is?

[mark.adams]

Breathers have definitely been cleaned, EGR valve was replaced as had a fault and then promptly blanked off with a coke can gasket.
I'll check the coolant temp reading when i get home although i haven't noticed it being wildly wrong recently... It starts okay with revs a little higher than normal until it warms up a bit then settles down as i would expect. Wife said it was quite a smoky exhaust when in the test station today.

[Marks DTM Calib]

Remember, we are looking for the ECU coolant temp, not the instrument panel reading 

[mark.adams]

Okay i have "My Naff Code Reader" on it now and the engine temp according to the ecu is matching the temp gauge on the dash almost exactly.
air fuel ratio bank1 sensor1 is flicking back and forward from lean to rich whilst b1s2 is solid on lean, on tickover at 757 revs